This application is for continuing support of a study, initiated in June 1991, whose main objectives are to determine whether persistent otitis media with effusion (OME) during the first 3 years of life results in lasting impairments of speech, language, cognitive, or psychosocial development, and if so, whether prompt tympanostomy-tube placement (TTP) prevents or lessens the impairments. Secondary objectives are to determine whether increasing the duration of OME required before undertaking TTP results in fewer operations or in altered long-term otologic or audiologic outcomes, and to chart the occurrence and course of otitis media (OM) and associated hearing loss in young children, distorted as little as possible by surgical interventions. Previous studies of OM in relation to later developmental impairment have been inconclusive and contradictory, and unsuited, because of their associational design, to address the issue of causality. A total of 6400 well infants aged <2 mo from 2 hospitals and 6 private pediatric practices will have been enrolled over a 54-month period ending Dec 1995. Their middle-ear status is monitored monthly. Those who develop acute OM or persistent OME receive antimicrobials. In those with long > 8 wk duration audiometry is scheduled monthly. Up to age 3 yr, children who reach specified criteria regarding persistent OME are, subject to consent, randomized to receive TTP either promptly ("early-TTP") or after a defined extended period if OME remains present ("late-TTP"). Thus a high-OME population is divided into 2 groups who can be assumed to have equivalent developmental potential: an early-TTP group most of whom become relatively OM-free, and a late-TTP group most of whom continue to have OM for varying periods. If the late group subsequently has less favorable developmental outcomes, persisting OM will presumably have been causal. Development is assessed subjectively in all subjects at ages 1 and 2 yr via parent questionnaires. Formal tests of speech, language, cognition, and psychosocial development are administered at ages 3, 4, and 6 yr to all subjects who had met randomization criteria and to a sample of others representing a spectrum of OME experience. Analyses of test results in these groups will enable determinations of whether associations, either short- or long-term, exist between persistent early OME and later developmental impairments; if so, whether the associations are causal; and whether prompt TTP is effective in preventing or lessening such impairments. As of Oct 5, 1995, 6030 children had been enrolled, 376 had met randomization criteria, and 292 had been randomly assigned to early- or late-TTP groups. Analyses to date have provided new information about the epidemiology of OM, about the diagnostic predictive value of tympanometry, and about correlations between cumulative OME duration and language and behavior at ages 1 and 2 yr. If continued, this study will provide new knowledge that will make possible more rational, evidence-based management of OM in infants and young children, and thereby benefit children and substantially influence child health care practices and costs.